What types of seventh chords is the minor NOT used?

* Major seventh chords: These chords are built on a major triad (i.e., a triad that contains a major third and a perfect fifth) with a seventh added a major seventh above the root. Minor sevenths are not used in major seventh chords because they would create dissonance between the major third and the seventh.

* Dominant seventh chords: These chords are built on a dominant seventh (i.e., a seventh chord that contains a major third, a perfect fifth, and a flattened seventh). Minor sevenths are not used in dominant seventh chords because they would create dissonance between the major third and the seventh.

* Half-diminished seventh chords: These chords are built on a minor triad (i.e., a triad that contains a minor third and a perfect fifth) with a flattened seventh added a half step below the root. Minor sevenths are used in half-diminished seventh chords to create the characteristic sound of the chord.

* Diminished seventh chords: These chords are built on a diminished triad (i.e., a triad that contains a minor third and a flattened fifth) with a flattened seventh added a half step below the root. Minor sevenths are used in diminished seventh chords to create the characteristic sound of the chord.